package demo1;

import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: mirac
 * Date: 2025-07-24
 * Time: 17:49
 */

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s1 = scanner.nextLine();
        String s2 = scanner.nextLine();

        StringBuilder result = new StringBuilder();
        for (char c : s1.toCharArray()) {
            if (s2.indexOf(c) == -1) {
                result.append(c);
            }
        }
        System.out.println(result.toString());
    }
}



/*
import java.util.Scanner;

public class BinaryAdd {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String a = scanner.nextLine();
        String b = scanner.nextLine();

        int i = a.length() - 1, j = b.length() - 1;
        int carry = 0;
        StringBuilder result = new StringBuilder();

        while (i >= 0 || j >= 0 || carry > 0) {
            int sum = carry;
            if (i >= 0) sum += a.charAt(i--) - '0';
            if (j >= 0) sum += b.charAt(j--) - '0';

            result.append(sum % 2);
            carry = sum / 2;
        }

        System.out.println(result.reverse().toString());
    }
}*/
